Facultad
de Psicología.Universidad de Granada.

18071.
Granada. SPAIN

ABSTRACT:The
number of hours of sleep, approximately 8, is an average that varies
little from one culture to another. However, there are individual
differences for this variable, which has permitted the establishment of
certain sleep patterns. Many studies have focused on the relationship
between psychological variables and sleep patterns, which have produced
contradictory results. The purpose of the present investigation is to
evaluate the extent of dimensions of extraverted and neurotic
personalities and state-trait anxiety levels in women with different sleep
patterns. In a sample of 300 young healthy adults, 34 women were selected,
17 women showed a long sleep pattern, 9 showed an intermediate sleep
pattern and 8 showed a short sleep pattern (age X = 20.29 SD = 1.55). The
results indicate that there are no significant statistical differences
between psychological variables and sleep patterns, which concludes that
there exists no relation between sleep duration and personality and
anxiety factors.

In
order to function adequately and to adapt to an environment, living
organisms need to sleep for a number of hours. The necessary number of
hours for human beings depend on biological, behavioral and environmental
factors. As a result, certain sleep patterns have been established which
characterize each individual. Sleep patterns are measurements that
identify the presence of sleep within a 24 hours period. The indicators
for these patterns are the onset and the completion of sleep [1].
Consistent with this, different sleep patterns exist within sleep
duration. Short-sleep pattern individuals usually sleep 6 hours or less,
and long-sleep pattern individuals sleep 9 or more hours. Both are extreme
sleep patterns which are characteristic of people with heterogeneous life
styles. Most people sleep between 6 ½ and8 hours, which refers to an intermediate sleep pattern [2].

Many
authors have investigated psychological variables and sleep patterns.
However, results have been inconsistent in establishing conclusive
results. Hartmann et al [3] reported that long-sleep pattern individuals
are more introverted and neurotic than short-sleep pattern individuals.
Skinner [4] supported these findings in a study with university students.
Wagner et al [5] found that long-sleep pattern individuals have a tendency
to score higher on pathological traits of the MMPI clinical measures.
Hartmann et al [3] concluded that with respect to neurotic disorders,
long-sleep pattern individuals possess significantly higher anxiety levels
than short-sleep pattern individuals. Chattopadhyay et al [6] conducted a
study with children and obtained similar results. Children with long-sleep
patterns were more anxious, introverted and neurotic than children with
short-sleep patterns. However, according to Hicks et al [7] short-sleep
pattern individuals were more anxious than long sleep pattern individuals.
Kumar et al [8] found similar results in the Indian population, where
short-sleep pattern individuals presented higher levels of neuroticism.

Due
to topic controversy, Webb [9] revised most relevant studies on this
subject. He concluded that differences found by others concerning the
personality traits of both groups really have not been proven. Buela-Casal
et al [10] confirmed these results. These authors concluded that
differences found in long- and short-sleep pattern individuals, apart from
sleep duration, are not proven [2,11].Due to existing controversial results about sleep duration and its
relation to personality traits, the purpose of the present investigation
is to evaluate if the intermediate, short- and long-sleep pattern
individuals showed differences in the personality traits of extroversion
and neuroticism, and in the variable referred to as state-trait anxiety.

METHODS

Research
participants

The
first selection phase of Research participants was composed of 300 young
adults.In the second phase,
a sample of 34 women between the ages of 19 and 25 years was selected (X =
20.29 years SD = 1.55). The sample of 34 women contained 17 long sleep
pattern individuals, 9 intermediate sleep pattern individuals and 8 short
sleep pattern individuals.

Instruments

-Sleep
Behavior and Habits Questionnaire.
The questionnaire consists of 8 questions concerning sleep habits and the
person’s vigil at different moments of their life.This same questionnaire classifies the individuals into three
categories: short, intermediate and long sleep patterns [11].

-State
Trait Anxiety Inventory(STAI)
[13].
This test evaluates two anxiety elements: anxiety as a state and anxiety
as a trait.

Procedure

The
Sleep Behavior and Habits questionnaire was administered to the original
sample of individuals in order to classify the individuals according to
their sleep pattern. From this first group, the sample of 34 women was
obtained and each one voluntarily accepted to participate in the
experiment. Of the 34 women, 17 showed a long sleep pattern, 9 showed an
intermediate sleep pattern and 8 showed a short sleep pattern. All of the
34 women were individually administered the tests, with the first being
the STAI and the second being the EPI Form A.

RESULTS

As
seen in Table 1, the results the Kruskal-Wallis test indicate that there
are no significant statistical differences between the three groups with
respect to the scores obtained on the EPI for the neuroticism variable [c2
= 0,84;p<0,65] as well as the extroversion variable [c2
= 2,30;p<0,32]. All the groups scored within an intermediate range for
neuroticism and within a high range for extraversion. The ANOVA results
reveal no significant statistical differences between the three groups
when referring to an anxiety state [c2
= 0,10;
p<0,95] and an anxiety trait [c2
= 2,40;p<0,30], as seen in Table 2.

Table
1. Summary
of averages, typical deviations and Kruskal-Wallis test obtained by
the three groups in the neuroticism and extroversion variables of
the EPI.

SLEEP
PATTERNS

SHORT

INTERMEDIATE

LONG

EPI

Average

SD

Average

SD

Average

SD

c2

p

Neuroticism

8.25

1.49

8.44

4.42

7.70

4.12

0,84

0,65

Extraversion

15.50

5.63

16.89

3.72

15.06

1.98

2,30

0,31

*p< 0.05

DISCUSSION

In
general, the results repeat the findings of various authors on the topic.
All investigations carried out contrast only extreme patterns, for which
it is important to point out that the present study has been included in
the third group. After an analysis of the results, we observe the same
tendency found in working with extreme patterns; there are no differences
with respect to the psychological variables (extraversion, neuroticism and
state-trait anxiety) in individuals with distinct sleep patterns. These
results agree with those found by Webb et al [14] and Buela-Casal et al
[10,11], among other authors. However, the results differ with those found
by Hartmann et al [3], Hicks et al [7], and more recently with those of
Chattopadhyay et al [6], who found psychological differences related to
sleep patterns. Webb’s conclusion is confirmed, which acknowledges that
differences between sleep patterns in relation to personality variables
are not proven, making evident that the difference between the 3 groups
being studied are fundamentally from sleep duration [9].

The
information obtained, once again, demonstrates that there is no
relationship between the psychological variables and sleep patterns.
However, it would be important to associate the sleep patterns with
physical and physiological variables. Likewise, the future remains open
for those interested in the field, to include varied sleep pattern
individuals and compare the results.

Table
2. Summary
of the results obtained by the three groups for the state- trait
anxiety variables.